Substantial regional differences in human herpesvirus 8 seroprevalence in sub‐Saharan Africa: Insights on the origin of the “Kaposi's sarcoma belt”

Abstract

Equatorial Africa has among the highest incidences of Kaposi's sarcoma (KS) in the world, thus earning the name “KS Belt.” This was the case even before the HIV epidemic. To date, there is no clear evidence that HHV‐8 seroprevalence is higher in this region but interpretation of the available literature is tempered by differences in serologic assays used across studies. We examined representatively sampled ambulatory adults in Uganda, which is in the “KS Belt,” and in Zimbabwe and South Africa which are outside the Belt, for HHV‐8 antibodies. All serologic assays were uniformly performed in the same reference laboratory by the same personnel. In the base‐case serologic algorithm, seropositivity was defined by reactivity in an immunofluorescence assay or in 2 enzyme immunoassays. A total of 2,375 participants were examined. In Uganda, HHV‐8 seroprevalence was high early in adulthood (35.5% by age 21) without significant change thereafter. In contrast, HHV‐8 seroprevalence early in adulthood was lower in Zimbabwe and South Africa (13.7 and 10.8%, respectively) but increased with age. After age adjustment, Ugandans had 3.24‐fold greater odds of being HHV‐8 infected than South Africans (p < 0.001) and 2.22‐fold greater odds than Zimbabweans (p < 0.001). Inferences were unchanged using all other serologic algorithms evaluated. In conclusion, HHV‐8 infection is substantially more common in Uganda than in Zimbabwe and South Africa. These findings help to explain the high KS incidence in the “KS Belt” and underscore the importance of a uniform approach to HHV‐8 antibody testing.

Human herpesvirus 8 (HHV-8) salivary shedding in mothers and children from Uganda: risk factors and clues about transmission

“…However, unexpectedly, we found a significant higher prevalence of the virus in female children's saliva. Despite it is known that African Kaposi Sarcoma affects mainly male population, the infection in endemic areas seems to occur with the same frequency in both gender (4,6,7,11,12). Thus, the data we found are not in agreement with previous studies.…”

“…Interestingly, in Amerindian tribes HHV-8 is hyperendemic showing the highest infection rates ever reported (about 80% in adults) (9,10). In Uganda HHV-8 seroprevalence ranges from 26.6% in children to 40.1% in adults showing an age dependent increase during childhood (7,11,12). In several studies is reported that saliva is the major reservoir of HHV-8 (5,9,12).…”

“…Thus, KS emerges as an important problem in sub-Saharan African public health; the investigation of HHV-8 transmission route in these areas represents a key factor in the reduction of KS incidence. HHV-8 seroprevalence in sub-Saharan Africa ranges from 40 to 70% in adults (6)(7)(8) while in Mediterranean countries is reported to be 16.5-18.7% (8). Interestingly, in Amerindian tribes HHV-8 is hyperendemic showing the highest infection rates ever reported (about 80% in adults) (9,10).…”

Childhood cancer incidence in South Africa, 1987 - 2007

“…[11] This may be explained by the comparatively low rates of endemic Kaposi's sarcoma in SA [16] and the lower prevalence of human herpesvirus infection in SA than, for example, in Uganda. [17] The overall incidence rates for the white population (ASR 116.2 per million) are rather low, but comparable with rates observed in the 1980s in some populations of South America (ASR 118 -136 per million) and Eastern Europe (ASR ~125 per million). [10] The higher incidence rates in the white compared with the black African population may be explained by a better rate of diagnosis and access to tertiary healthcare treatment in a POU.…”

A Review of Human Herpesvirus 8, the Kaposi's Sarcoma-Associated Herpesvirus, in the Pediatric Population

“…The "KS belt" is a region in equatorial Africa where even before HIV, the progression of HHV-8 to endemic KS was particularly high [16]. The belt extends from the coast of Cameroon through northeast Democratic Republic of Congo and down the Rift Valley to Malawi including Uganda, Tanzania, and Zambia [17].…”